Microsoft announced today that it is beginning the rollout of Windows Phone 8.1 to its Nokia devices worldwide, which will include the Lumia Cyan firmware, bringing unique improvements and customizations specific to these handsets.

The company said that the update "will be available for all Windows Phone 8 Lumia devices in the coming weeks." Of course, that means that if you're still using Windows Phone 7.8, your handset won't be updated - although given that it's been two years since Microsoft dead-ended that generation of devices, you should be used to that by now.

But if you've got a Windows Phone 8 Lumia handset, when can you expect to receive the update? As with its previous updates, Nokia has provided a handy page detailing when every one of its WP8 devices around the world will receive Windows Phone 8.1 and Cyan.

Handsets are grouped by region and nation, with individual variants - such as unlocked and carrier-specific models - each listed with the availability status of the update. Most devices still list the update as 'under testing'; when this changes to 'available', you will be able to download and install 8.1 and Cyan on to your Lumia handset.

The same page also includes information on installing the update. Microsoft advises that you will need at least 1.5GB of free space on your device to "ensure that your software update will go smoothly."